move inspect from server to daemon

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)
Update gorilla/mux, gorilla/context, and kr/pty deps

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #5950 from tianon/update-deps

Update gorilla/mux, gorilla/context, and kr/pty deps
Merge pull request #5755 from vieux/move_inspect_daemon

move inspect from server to daemon
Mount /dev in tmpfs for privileged containers
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Update documentation for container struct in libcontainer
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)